• Applied Biological Chemistry
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• v.24 no.3
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• pp.161-166
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• 1981

Products of ginseng browning reaction were investigated to determine the nature of their antioxidant activity using a model system, White Ginseng and Red Ginseng extracts. In the simulated ginseng model system, the brown color was intensified with an increase in the length of reaction time and the antioxidant activity initially increased in proportion the length of reaction time for up to 17 hrs and then leveled off thereafter. Pararell results were obtained manufacturing of Red Ginseng, Comparison of the antioxidant activity of the inner and outer solutions after dialysis of browning solution showed that the outer solution had a stronger antioxidant activity than the inner one. For further analyses, browning reaction products were fractionated into three peaks on Amberlite CG-120 type I ionexchange resin and designated as fractions I, II and III in order of elution. Partial characterization of the fractions revealed that floe most intense brown fraction (Fraction II) had the strongest antioxidant activity and also exhibited reducing power for Somogyi-Nelson reagents and ninhydrin positive reaction. Both the browning reaction products and Red Ginseng extracts were found to possess potent reactivity with ${\alpha}$,${\alpha}'$-diphenyl-${\beta}$-picrylhydrazyl, whereas White Ginseng extracts showed negligible reactivity.

• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.8-13
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• 2013

Persons with sensorineural hearing impairment have troubles in hearing at noisy environments because of their deteriorated hearing levels and low-spectral resolution of the auditory system and therefore, they use hearing aids to compensate weakened hearing abilities. Various algorithms for hearing loss compensation and environmental noise reduction have been implemented in the hearing aid; however, the performance of these algorithms vary in accordance with external sound situations and therefore, it is important to tune the operation of the hearing aid appropriately in accordance with a wide variety of sound situations. In this study, a sound classification algorithm that can be applied to the hearing aid was suggested. The proposed algorithm can classify the different types of speech situations into four categories: 1) speech-only, 2) noise-only, 3) speech-in-noise, and 4) music-only. The proposed classification algorithm consists of two sub-parts: a feature extractor and a speech situation classifier. The former extracts seven characteristic features - short time energy and zero crossing rate in the time domain; spectral centroid, spectral flux and spectral roll-off in the frequency domain; mel frequency cepstral coefficients and power values of mel bands - from the recent input signals of two microphones, and the latter classifies the current speech situation. The experimental results showed that the proposed algorithm could classify the kinds of speech situations with an accuracy of over 94.4%. Based on these results, we believe that the proposed algorithm can be applied to the hearing aid to improve speech intelligibility in noisy environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2783-2790
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• 2010

In this paper, we first review LDPC codes in general and a belief propagation algorithm that works in logarithm domain. LDPC codes, which is chosen 802.11n for wireless local access network(WLAN) standard, require a large number of computation due to large size of coded block and iteration. Therefore, we presented three kinds of low computational algorithms for LDPC codes. First, sequential decoding with partial group is proposed. It has the same H/W complexity, and fewer number of iterations are required with the same performance in comparison with conventional decoder algorithm. Secondly, we have apply early stop algorithm. This method reduces number of unnecessary iterations. Third, early detection method for reducing the computational complexity is proposed. Using a confidence criterion, some bit nodes and check node edges are detected early on during decoding. Through the simulation, we knew that the iteration number are reduced by half using subset algorithm and early stop algorithm is reduced more than one iteration and computational complexity of early detected method is about 30% offs in case of check node update, 94% offs in case of check node update compared to conventional scheme. The LDPC decoder have been implemented in Xilinx System Generator and targeted to a Xilinx Virtx5-xc5vlx155t FPGA. When three algorithms are used, amount of device is about 45% off and the decoding speed is about two times faster than convectional scheme.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.1-13
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• 2014

Lithium ion batteries (LIBs) are the state-of-the-art technology among electrochemical energy storage and conversion cells, and are still considered the most attractive class of battery in the future due to their high specific energy density, high efficiency, and long cycle life. Rapid development of power-hungry commercial electronics and large-scale energy storage applications (e.g. off-peak electrical energy storage), however, requires novel anode materials that have higher energy densities to replace conventional graphite electrodes. Germanium (Ge) and silicon (Si) are thought to be ideal prospect candidates for next generation LIB anodes due to their extremely high theoretical energy capacities. For instance, Ge offers relatively lower volume change during cycling, better Li insertion/extraction kinetics, and higher electronic conductivity than Si. In this focused review, we briefly describe the basic concepts of LIBs and then look at the characteristics of ideal anode materials that can provide greatly improved electrochemical performance, including high capacity, better cycling behavior, and rate capability. We then discuss how, in the future, Ge anode materials (Ge and Ge oxides, Ge-carbon composites, and other Ge-based composites) could increase the capacity of today's Li batteries. In recent years, considerable efforts have been made to fulfill the requirements of excellent anode materials, especially using these materials at the nanoscale. This article shall serve as a handy reference, as well as starting point, for future research related to high capacity LIB anodes, especially based on semiconductor Ge and Si.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.27-45
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• 2021

The purpose of this study is to trace the path of policy for urban parks and greenbelts (PUPG) pursued by Seoul Mayor Kim Hyeon-ok, who was a protagonist of Seoul's modernization and to reveal the policy's characteristics. A high modernism perspective was projected to advance his PUPG discussion. High modernism was an unavoidable phenomenon that appeared in post-war urban reconstruction projects and emerged in the form of a belief that the national elite creates the ideal social order and rational planning. Its characteristics were to build with legibility, immediacy, and convenience by power, with private participation and profit creation, while realizing the spectacle of "the city being built". As a high-modernist, Seoul Mayor Kim Hyun-ok's urban planning aimed to deal with the booming population and the expansion of Seoul's territory. Although his PUPG extended the parks to the outskirts of Seoul, he showed a dualistic attitude, diverting parks away from the city center. On the other hand, he induced the participation of the private sector to create parks. However, he showed the other side of modernization, eliminating the placeness and excluding related systems. The path taken by Mayor Kim Hyun-ok's PUPG was started to respond to population growth and resolve the encroachment of parks. The ultimate goal was to accept the realization of urban planning and experiment with non-financial methods. The characteristics of his PUPG reflecting high modernism were: First, elites were represented in the National Land Planning Association, HURPI, and Jang Moon-gi participated; second, legibility was ensured by using east-west and north-south axes, elevation standards, and rational planning. Third, parks were quickly released to respond to the rapid urban change. Fourth, it showed off events and spectacles to attract private capital.

• (The)Study of the Eastern Classic
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• no.34
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• pp.339-362
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• 2009

If we try to define the concept of beauty in the large sense, as Kant and Chaung-tzu all agree, It can not be fixed in the one sense, but whose connotation and denotation should be extended infinitely. In this sense, I would like to say that the beauty is liberty. Aesthetics of Kant is oriented toward subjective and reflexive dimension, while that of Chuang-tzu is oriented toward natural and practical one. The difference between aesthetics of the two philosophers begins from their philosophical methodology. If the transcendental methode which is proper to Kant's philosophy prefers to discriminate and devide everything especially from dichotomic viewpoint by langage. But Chuang-tzu' methode called Za-Mang criticizes such a dichotomic division and langage itself. Even so, the two in the long run agree as to the foundation of beauty. But Kant's liberty is one of will or transcendental, meanwhile that of Chuang-tzu is based on recognize the fact that we are all production of nature. according to Chuang-tzu, in the great beginning, there was non-being. It had neither being nor name. The One originates from it. When things obtain it and come into existence. As the One, Tao is in the excrement and urine. Everything is under the constant flux. All species have originative or moving power. Although the universe is vast, its transformation is uniform. Because all things are one. Vacuity, tranquillity, mellowness, quietness, and taking no action characterize the things of universe at peace and represent the ultimate of Tao and virtue. The material was transformed to be form, form was transformed to become life, and now life has transformed to become death. A basic principle of Chuang-tzu's art is expressed in the phrase "taking off clothes and squatting down bare-backed". The key of Chuang-tzu's aesthetics is to dedicate to the expression of inner spirit instead of physical verisimilitude, and painting should be a spontaneous and instantaneous flow of the brush. Kant's concepts such as "disinterested" and "purposiveness of nature" seem to imply in the long run the unification of nature and human being which is fundament to Chuang-tzu's aesthetics.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.396-407
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• 2020

As fossil fuels are depleted worldwide, alternative resources is required to replace fossil fuels, and biofuels are in the spotlight as alternative resources. Biofuels are produced from biomass, which is a renewable resource to produce biofuels or bio-chemicals. Especially, in order to substitute fossil fuels, the research focusing the biofuel (biodiesel) production based on CO₂ and biomass achieves more attention recently. To produce biomass-based biodiesel, the development of a supply chain network is required considering the amounts of feedstocks (ex, CO₂ and water) required producing biodiesel, potential locations and capacities of bio-refineries, and transportations of biodiesel produced at biorefineries to demand cities. Although many studies of the biomass-based biodiesel supply chain network are performed, there are few types of research handled the uncertainty in CO₂ supply which influences the optimal strategies of microalgae-based biodiesel production. Because CO₂, which is used in the production of microalgae-based biodiesel as one of important resources, is captured from the off-gases emitted in power plants, the uncertainty in CO₂ supply from power plants has big impacts on the optimal configuration of the biodiesel supply chain network. Therefore, in this study, to handle those issues, we develop the two-stage stochastic model to determine the optimal strategies of the biodiesel supply chain network considering the uncertainty in CO₂ supply. The goal of the proposed model is to minimize the expected total cost of the biodiesel supply chain network considering the uncertain CO₂ supply as well as satisfy diesel demands at each city. This model conducted a case study satisfying 10% diesel demand in the Republic of Korea. The overall cost of the stochastic model (US$ 12.9/gallon·y) is slightly higher (23%) than that of the deterministic model (US$ 10.5/gallon·y). Fluctuations in CO₂ supply (stochastic model) had a significant impact on the optimal strategies of the biodiesel supply network.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.58-68
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• 2006

This work proposes a 10b 250MS/s $1.8mm^2$ 85mW 0.13um CMOS A/D Converter (ADC) for high-performance integrated systems such as next-generation DTV and WLAN simultaneously requiring low voltage, low power, and small area at high speed. The proposed 3-stage pipeline ADC minimizes chip area and power dissipation at the target resolution and sampling rate. The input SHA maintains 10b resolution with either gate-bootstrapped sampling switches or nominal CMOS sampling switches. The SHA and two MDACs based on a conventional 2-stage amplifier employ optimized trans-conductance ratios of two amplifier stages to achieve the required DC gain, bandwidth, and phase margin. The proposed signal insensitive 3-D fully symmetric capacitor layout reduces the device mismatch of two MDACs. The low-noise on-chip current and voltage references can choose optional off-chip voltage references. The prototype ADC is implemented in a 0.13um 1P8M CMOS process. The measured DNL and INL are within 0.24LSB and 0.35LSB while the ADC shows a maximum SNDR of 54dB and 48dB and a maximum SFDR of 67dB and 61dB at 200MS/s and 250MS/s, respectively. The ADC with an active die area of $1.8mm^2$ consumes 85mW at 250MS/s at a 1.2V supply.

• The Journal of Korean Philosophical History
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• no.35
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• pp.43-71
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• 2012

Rural Neo-Confucian Literati were major governing elite in Joseon Dynasty. They were small and medium-sized landowners all over the country and elite having Confucian knowledge. They formed villages of the same family name and exerted their influence on the community showing off their successful ancestors. Therefore, there were lots of examples that they took the actual leadership in local communities. In this sense, the Hwacheon-gun pa family line of the Andong Kweon clan were the representative rural neo-Confucian literati of Hwang-gang and Shindong areas in Jecheon. This group was formed after Kweon Sangha and his brothers' movement in 1675. Kweon was the best pupil of Song Siyeol, a prominent scholar and man of power. Although facing away the government examination, he was respected as sallim, rustic literati, on account of his teaching and writing activities and later called to High State Councillor. After his death, memorial halls and facilities to worship him, including Hwang-gang Sowon Academy, were built in the place he taught students. These facilities contributed to his descendants' acquiring his life values. They also made a contribution to the settlement of reject-heterodoxy sentiments based on their loyalty to the Myeong Dynasty in the area. Kweon Seop, Kweon Sangha's nephew, also played an important role in Hwacheon-gun pa family line's growing as rural neo-Confucian literati in Jecheon area. He built memorial halls to enshrine Kweon Sangha and made rules to develop his family line. In addition, he extended their living space over Hwang-gang area and each place had the shrine to hold a memorial service for their ancestors. As a result, Kweon Sangha and Kweon Seop's family wielded power in Jecheon for hundreds years as the same family name group. Rural neo-Confucian literati didn't produce more elite government officials than the groups in the capital, but their growth enabled cultural development of the local community and the Joseon Dynasty.

• Journal of Korean Academy of Nursing
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• v.13 no.1
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• pp.7-21
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• 1983

For the flexible and rational distribution of limited existing health resources based on measurements of individual risk, the socalled Risk Approach is being proposed by the World Health Organization as a managerial tool in maternal and child health care program. This approach, in principle, puts us under the necessity of developing a technique by which we will be able to measure the degree of risk or to discriminate the future outcomes of pregnancy on the basis of prior information obtainable at prenatal care delivery settings. Numerous recent studies have focussed on the identification of relevant risk factors as the Prior infer mation and on defining the adverse outcomes of pregnancy to be dicriminated, and also have tried on how to develope scoring system of risk factors for the quantitative assessment of the factors as the determinant of pregnancy outcomes. Once the scoring system is established the technique of classifying the patients into with normal and with adverse outcomes will be easily de veloped. The scoring system should be developed to meet the following four basic requirements. 1) Easy to construct 2) Easy to use 3) To be theoretically sound 4) To be valid In searching for a feasible methodology which will meet these requirements, the author has attempted to apply the“Likelihood Method”, one of the well known principles in statistical analysis, to develop such scoring system according to the process as follows. Step 1. Classify the patients into four groups: Group $A_1$: With adverse outcomes on fetal (neonatal) side only. Group $A_2$: With adverse outcomes on maternal side only. Group $A_3$: With adverse outcome on both maternal and fetal (neonatal) sides. Group B: With normal outcomes. Step 2. Construct the marginal tabulation on the distribution of risk factors for each group. Step 3. For the calculation of risk score, take logarithmic transformation of relative proport-ions of the distribution and round them off to integers. Step 4. Test the validity of the score chart. h total of 2, 282 maternity records registered during the period of January 1, 1982-December 31, 1982 at Ewha Womans University Hospital were used for this study and the“Questionnaire for Maternity Record for Prenatal and Intrapartum High Risk Screening”developed by the Korean Institute for Population and Health was used to rearrange the information on the records into an easy analytic form. The findings of the study are summarized as follows. 1) The risk score chart constructed on the basis of“Likelihood Method”ispresented in Table 4 in the main text. 2) From the analysis of the risk score chart it was observed that a total of 24 risk factors could be identified as having significant predicting power for the discrimination of pregnancy outcomes into four groups as defined above. They are: (1) age (2) marital status (3) age at first pregnancy (4) medical insurance (5) number of pregnancies (6) history of Cesarean sections (7). number of living child (8) history of premature infants (9) history of over weighted new born (10) history of congenital anomalies (11) history of multiple pregnancies (12) history of abnormal presentation (13) history of obstetric abnormalities (14) past illness (15) hemoglobin level (16) blood pressure (17) heart status (18) general appearance (19) edema status (20) result of abdominal examination (21) cervix status (22) pelvis status (23) chief complaints (24) Reasons for examination 3) The validity of the score chart turned out to be as follows: a) Sensitivity: Group $A_1$: 0.75 Group $A_2$: 0.78 Group $A_3$: 0.92 All combined : 0.85 b) Specificity : 0.68 4) The diagnosabilities of the“score chart”for a set of hypothetical prevalence of adverse outcomes were calculated as follows (the sensitivity“for all combined”was used). Hypothetidal Prevalence : 5％ 10％ 20％ 30％ 40％ 50％ 60％ Diagnosability : 12% 23% 40% 53% 64% 75% 80%.